Ballast circuit for a plurality of lamps

ABSTRACT

A circuit for lighting a plurality of lamps requiring a temporary starting voltage and an operating voltage of a different value than the starting voltage. The starting voltage source is switched completely out of the line during operation. An impedance device is provided in series with the lamps which is preferably a capacitor. Since the starting voltage is turned on for only a short period of time, the starting voltage source may be of a small power output requirement compared with the main power source.

United States Patent 1191 Spiteri [4 Aug. 6, 1974 BALLAST CIRCUIT FOR A PLURALITY OF LAMPS [75] Inventor: Joseph Spiteri, Erie, Pa.

[73] Assignee: Rem Research, Inc., Erie, Pa.

[22] Filed: Aug. 29, 1972 [21] Appl. No.: 284,568

[52] US. Cl..... 315/161, 315/317, 315/320, 315/322 [51] Int. Cl. 1-105b 37/00 [58] Field of Search 3l5/DlG. 5, 160, 161, 313, 315/317, 320, 321, 322

[56] References Cited UNITED STATES PATENTS 3,365,648 1/1968 Benjamin 315/D1G. 5

FOREIGN PATENTS OR APPLICATIONS 850,961 10/1960 Great Britain 3l5/DIG. 5

Primary ExaminerHerman Karl Saalbach Assistant Examinerlames B. Mullins 5 7] ABSTRACT A circuit for lighting a plurality of lamps requiring a temporary starting voltage and an operating voltage of a different value than the starting voltage. The starting voltage source is switched completely out of the line during operation. An impedance device is provided in series with the lamps which is preferably a capacitor. Since the starting voltage is turned on for only a short period of time, the starting voltage source may be of a small power output requirement compared with the main power source.

6 Claims, 1 Drawing Figure BALLAST CIRCUIT FOR A PLURALITY OF LAMPS OBJECTS OF THE INVENTION It is an object of the invention to provide a starting circuit which is economical to manufacture, light weight, and economical to operate and maintain.

Another object of the invention is to provide a fluorescent light circuit that operates directly on line voltage without a starting ballast, as commonly known.

Another object of the invention is to provide an improved ballast arrangement for a plurality of tlourescent tubes.

Another object of the invention is to provide a fluo rescent light circuit with a capacitor impedance memher.

With the above and other objects in view, the present invention consists of the combination and arrangement of parts hereinafter more fully described, illustrated in the accompanying drawing and more particularly pointed out in the appended claims, it being understood that changes may be made in the form, size, proportions, and minor details of construction without departing from the spirit or sacrificing any of the advantages of the invention.

GENERAL DESCRIPTION OF THE DRAWING DETAILED DESCRIPTION OF THE DRAWINGS The circuit is made up generally of the selector switch 10, two relays 56 and 62, and an autotransformer 71 which provides a high voltage for starting the lamps. The autotransformer 71 has primaries 69 and 72 which are connected to lines 52 and 53. The secondary terminals which include the terminals 70 and 72 are connected through capacitors 73 and 74 to the movable contacts 75 and 76 of relay 62. The selector switch has 10 banks of fixed contacts, each bank having five fixed contacts distributed around the banks and 10 movable contacts. Each bank of fixed contacts has a movable contact. The movable contacts are all connected together so that they move in unison from position 1 to positions 2-6.

The banks of fixed contacts, each having a movable contact, are indicated at A through J.

The movable contacts 11 and 12 are connected to wires 65 and 66. When the on-off switch 80 is closed, the line power from 49 and 50 is connected through lines 81 and 82 to the movable contacts 13, 15 and 17 which are connected in parallel with each other and the movable contacts l4, l6 and 18 which are connected in parallel with each other. The movable contacts 19 and 20 are connected in series with the starter so that when the switch 10 is moved from position 1 through positions 2, 3, 4, and 5, the starter is selectively connected to the starters 41 and 43 of each of the tubes 36, 37, 38 and 39 in sequence. Thus a single starter performs the function previously performed by an individual starter for each lamp. The contact 2 of stage A of selector switch 10 is connected to fixed contacts 3, 4 and 5 of stage C. Fixed contact 3 of stage A is connected to fixed contacts 3, 4, 5 and 6 of stage E. Contact 4 of stage A is connected to terminal of tube 38 and fixed contact 5 of stage G. Contact 6 of stages A, B, C, D, G, H, I and J are not connected to anything. Fixed contact 2 of stage B is connected to terminal 42 of tube 36 and to fixed contacts 3, 4 and 5 of stage D. Fixed contact 3 of stage B is connected to terminal 42 of tube 37 and to terminals 4, 5 and 6 of stage F. Fixed contact 4 of stage B is connected to terminal 42 of tube 38 and to fixed contact 5 of stage H. Fixed contact 5 of stage B is connected to terminal 42 of tube 39.

The lamps 36, 37, 38 and 39 are all of a type of fluorescent lamp that is common to those skilled in the art. These fluorescent lamps have terminals 40, 41, 42 and 43. The terminals 41 and 43 of each of the tubes is connected to the heater of the tube and terminals 40 and 42 of each tube is connected to the cathode in a conventional manner. The capacity of reactance units, which are a form of capacitors 44, 45, 46 and 47, are capacitors of a size suitable to limit the current through the fluorescent lamp when the tube fires. Capacitors 44, 45, 46 and 47 also introduce a time delay at startmg.

When the movable contacts of switch 10 are in the number 1 position, none of the movable contacts are connected to any source of power connected to the fixed contacts. Thus when starting switch 80 is closed, 120 volt A.C. power connected to the lines 49 and 50 will provide a first voltage which will flow through the lines 52 and 53. Line 51 is connected to ground. The first voltage of 120 volts A.C. will flow through the movable relay 56. The transformer 71 at coil 48 provides a second voltage. Contacts 54 and 55 of relay 56 will be connected through lines 65 and 66 to the movable contacts 2 of stage A and stage B. When the movable contacts are moved to the number 2 position of switch 10, 120 volts A.C. will be connected to the terminals 40 and 42 of fluorescent lamp 36 and likewise to terminals 3, 4, and 5 of stage C and also terminals 3, 4, and 5 of stage D. The solenoid 75 and relay 56 is connected in parallel with capacitor 77 and full wave rectifier circuit 78. The solenoid 75 is connected through the push button switch 79 to line 53 and connected directly to line 52. When the starting switch 79 is pushed, the 120 volts A.C. will be connected to the coil 75 of relay 56 which will cause the movable contacts 54 and 55 to disengage the normally closed contacts 63 and 64 and to engage the normally open contacts 57 and 58 of relay 56. This will connect 120 volts A.C. to the bridge circuit 59 and A.C. will flow through the resistor 60 to the relay coil 61 and energize it. Thus the movable contacts 75 and 76 of relay 62 will engage the fixed contacts 67 and 68 of relay 62 and connect a high voltage from transformer 71 through capacitors 73 and 74 to the lines and 66 respectively. This high voltage will be connected across the terminals 40 and 42 of tube 36 through capacitor .44 and will start the tube.

When the tube 36 is started, then the switch 10 will be moved to the number 3 position. In this position, the transformer 71 will start tube 3. The switch 10 is then moved to the number 4 position. This will connect the power from the autotransformer terminals 70 and 72 to terminals 40 and 42 of tube 38.

It will be seen that when the selector switch 10 is moved to the number 4 position, the high voltage from the transformer 71 will be connected to the terminals 40 and 42 of the fluorescent lamp 38.

In the fifth position of switch 10, high voltage from terminals 70 and 72 of the autotransformer 71 are connected across the terminals 40 and 42 of the fluorescent lamp 39. Thus it will be noted that for each position of the selector switch 10, the high voltage from terminals 70 and 72 of relay 71 is impressed on one of the fluorescent lamps 36, 37, 38 and 39 successively. The resistor condenser circuit 60 in connection with full wave rectifier circuit 59 introduces a time delay between the time relay 56 closes and the time that relay 62 closes.

The stages I and J of the switch successively close the heater circuits of heater 35 through the heaters of the tubes 36, 37, 38 and 39. These heaters are connected across the terminals 40 and 41 and across the terminals 42 and 53 in a conventional manner.

When a conventional 40 inch fluorescent tube is used, the value of the capacitance of capacitors 44, 45, 46 and 47 should be approximately 12 microfarads (MF D). The capacitors are connected inseries with the terminals 40 of lamps 36, 37, 38 and 39 respectively and the A.C. line. After the fluorescent lamps start, the ballast transformer 71 is switched out of the circuit. The circuit is designed for preheat instant start and rapid start fluorescent lamps.

The starting ballast is very small in comparison with that normally used because it only has power connected to it a very short time and thereafter the tube is switched onto 120 volts A.C. very quickly. The relay 56 and its time constant components capacitor 77 and rectifier circuit 78', relay 62 with its time constant components rectifier 59, capacitor 60 and resistor 60 are held closed for the starting pulse voltage that is passed through capacitor 44 when the switch 10 is in the number 2 position. The heaters of lamp 36 are connected to starter 35.

When the selector switch 10 is in the number 3 position, the tube 36 is turned on, and when it is moved to the number 3 position, the filaments in tube 37 heat through heater 35, and so on. The ballast transformer 71 switches outof the circuit successively as the switch 10 is moved successively through its positions. The capacitors 44, 45, 46 and 47 can be built into the fluorescent tubes themselves thereby further simplifying the circuit and the multi-fluorescent tube ballast can be used.

The foregoing specification sets forth the invention in its preferred practical forms but the structure shown is capable of modification within a range of equivalents without departing from the invention which is to be understood is broadly novel as is commensurate with the appended claims.

The embodiments of the invention in which an exlusive property or privilege is claimed are defined as follows:

1. A circuit for starting lamps requiring an initial voltage and an operating voltage of a different voltage than the initial voltage comprising at least a first fluorescent lamp having heater terminals and cathode terminals and a second fluorescent lamp having heater terminals and cathode terminals,

a first source of starting voltage,

a second source of operating voltage,

means for temporarily connecting said first source of starting voltage to said cathode terminals,

and means for temporarily connecting said heater terminals together,

and means for connecting said second source of operating voltage to said cathode terminals of said first lamp and for disconnecting said first source of starting voltage from said cathode terminals,

and means for connecting said first source of starting voltage to said cathode terminals of said second fluorescent lamp and means for connecting said heater terminals of said second fluorescent lamp together whereby said first source of starting voltage directs a current through said heater terminals of said fluorescent lamps,

and means for disconnecting said first source of starting voltage from said cathode terminals and for connecting said second source of operating voltage to said cathode terminals of said second fluorescent lamp.

2. The circuit recited in claim 1 wherein an impedance is connected in series with each said lamp.

3. The circuit recited in claim 2 wherein said impedance is a capacitor.

4. The circuit recited in claim 1 wherein said first voltage source and said second voltage source are connected to said lamps through a first selector switch and a second selector switch having common terminals,

said first source of power is connected to the common terminals of said selector switches and said second source of voltage is connected to said first selector switch common terminal.

5. The circuit recited in claim 1 wherein said first voltage source comprises an autotransformer.

6. The circuit recited in claim 1 wherein said first source of starting voltage comprises an autotransformer,

said autotransformer has primary windings connected to said second source of operating voltage through a first relay. 

1. A circuit for starting lamps requiring an initial voltage and an operating voltage of a different voltage than the initial voltage comprising at least a first fluorescent lamp having heater terminals and cathode terminals and a second fluorescent lamp having heater terminals and cathode terminals, a first source of starting voltage, a second source of operating voltage, means for temporarily connecting said first source of starting voltage to said cathode terminals, and means for temporarily connecting said heater terminals together, and means for connecting said second source of operating voltage to said cathode terminals of said first lamp and for disconnecting said first source of starting voltage from said cathode terminals, and means for connecting said first source of starting voltage to said cathode terminals of said second fluorescent lamp and means for connecting said heater terminals of said second fluorescent lamp together whereby said first source of starting voltage directs a current through said heater terminals of said fluorescent lamps, and means for disconnecting said first source of starting voltage from said cathode terminals and for connecting said second source of operating voltage to said cathode terminals of said second fluorescent lamp.
 2. The circuit recited in claim 1 wherein an impedance is connected in series with each said lamp.
 3. The circuit recited in claim 2 wherein said impedance is a capacitor.
 4. The circuit recited in claim 1 wherein said first voltage source and said second voltage source are connected to said lamps through a first selector switch and a second selector switch having common terminals, said first source of power is connected to the common terminals of said selector switches and said second source of voltage is connected to said first selector switch common terminal.
 5. The circuit recited in claim 1 wherein said first voltage source comprises an autotransformer.
 6. The circuit recited in claim 1 wherein said first source of starting voltage comprises an autotransformer, said autotransformer has primary windings connected to said second source of operating voltage through a first relay. 